As automotive vehicles travel on wet road surfaces, the wheels and tires splash water and mud from the road surface. The tires also pick up water that tends to adhere to tire surfaces. The water that adheres to tire surfaces is thrown off the tire surfaces by centrifugal force. Water that is thrown from tires by centrifugal force is thrown radially outward relative to the rotating tire surface. The bulk of this water is thrown to the rear and up. The water forms droplets as it separates from the surface of a tire. The droplets of water vary in size. The portion of water thrown from tires that is in minute droplets increases as vehicle speed increases. It is also believed that the portion of the water that is in minute droplets increases as vehicle size and weight increase. Minute droplets of water that are thrown from vehicle tires by centrifugal force can become entrained in air. Entrained air and minute droplets of water produce a heavy wet fog, some of which floats up and out from the sides of the vehicle which created the fog. Heavy wet fog, individual water drops that spray from vehicle tires, and water that is splashed from road surfaces by vehicle tires can reduce visibility for other vehicles. At times, the windshield wipers on vehicles traveling into the heavy wet fog, spray of water drops, and splashed water and mud can become overloaded making it impossible to see through the water and past the vehicle windshield. These poor visibility problems are particularly serious for vehicles that are meeting each other on roads with two-way traffic and for a vehicle that is passing or being passed by another vehicle traveling the same direction.
The need to eliminate the visibility problems created by vehicle tire splash and tire spray has been recognized for many years. The U.S. Department of Transportation drafted rules requiring spray suppressant systems on large vehicles, such as trucks. The rules were not put into force when it became clear that effective technology has not been available to solve the problem.